It is a common experience among people familiar with painting that after placing the lid back on a partially used paint can and then re-opening it at a later date, a skin has formed on the surface of the stored paint. The removal of the skin is a difficult and messy task which often produces unsatisfactory results.
Often the skin will break-up and leave particles within the can which tend to mar the surface of the item or wall being painted.
The formation of the skin is caused by the reaction between the paint and the surrounding air. Even when a paint can is tightly sealed using the lid provided with the can an amount of air, such amount depending upon the amount of paint that remains in the can, is still trapped within the container. As a result, so long as such air is trapped within the can, an undesirable skin will form.
Previous devices have attempted to solve the above problem by isolating the paint within the can from any surrounding air. Examples of such devices are disclosed in the following U.S. Pat. Nos. 4,682,705; 2,828,886; 2,556,195; 4,625,883; 3,266,662 and 4,874,108.
These previous devices generally suffer from several problems. First, the devices disclosed are generally complex in construction. As a result of such complexity, their production is an expensive undertaking. Secondly, insertion of several of the previously known devices causes an amount of air to be trapped within the can between the sealing device and the contents of the container. Thirdly, such known devices do not permit easy removal from the contents of the container as a suction will be created when attempting to remove such devices from the surface of the contents.